Centrifugal pendulum absorbers are used in machines to reduce vibrations (e.g., torsional vibrations) of rotating components. In engines crankshafts, flywheels, etc., may generate torsional vibration. Centrifugal pendulum absorbers may be placed in engines to attenuate the torsional vibration. As a result, noise, vibration, and harshness (NVH) is decreased in the engine. Specifically, pendulum absorbers may be coupled to a crankshaft or a flywheel to dampen torsional vibrations, thereby increasing component longevity and decreasing engine noises.
US 2013/0233125 discloses a centrifugal pendulum absorber in an engine. The centrifugal pendulum absorber includes a preloaded spacing element placed between separate pendulum absorber elements to restrict movement (e.g., lock-up) of the pendulum absorber elements, thereby reducing NVH during low speed operation. The Inventors have recognized several drawbacks with centrifugal pendulum absorber disclosed in US 2013/0233125. For instance, the longevity of the spacing element in the absorber may be limited. In particular, the lifespan of spacing element may less than the other components in the pendulum absorber.
As such in one approach, a pendulum absorber assembly is provided. The pendulum absorber assembly includes a rotor coupled to a rotating shaft, a pendulum absorber moveably coupled to the rotor and including a preloaded sliding joint coupled to a first counterbalancing section and a second counterbalancing section, the preloaded sliding joint configured to urge the first counterbalancing section away from the second counterbalancing section, and two pins, each of the pins coupled to a different counterbalancing section and the rotor. In one example, each counterbalancing section includes a counterbalance pin opening mated with a corresponding pin. The preloaded sliding joint enables a constant force to be exerted on the pin openings by the pins during low speed operation of the crankshaft to reduce vibration caused by play between the pins and pin openings. In other words, the float of the pin in the pin opening is substantially inhibited at low engine speeds. As a result, NVH generated by the drive-train is reduced, thereby increasing customer satisfaction and increasing transmission longevity.
The above advantages and other advantages, and features of the present description will be readily apparent from the following Detailed Description when taken alone or in connection with the accompanying drawings.
It should be understood that the summary above is provided to introduce in simplified form a selection of concepts that are further described in the detailed description. It is not meant to identify key or essential features of the claimed subject matter, the scope of which is defined uniquely by the claims that follow the detailed description. Furthermore, the claimed subject matter is not limited to implementations that solve any disadvantages noted above or in any part of this disclosure. Additionally, the above issues have been recognized by the inventors herein, and are not admitted to be known.